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12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
Originally Posted by skratch77
Roadkill what are your mods to the car? Are you running headers?
Just Eurocharged, secondary cat delete and row airboxes. Removed the tune and the secondary cat delete and still had the high ltft's which is when I tried switching to stock airboxes to get ltft's back to normal.
12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
Ok, finally got my ROW airboxes back in after sealing them - mine were very good form the factory, tiny gap I could see light through, sealed them very well and it makes 100% zero difference on my car.
Also notable, MAF's see exactly the same amount of air passing them on both lids, no noticeable difference to what the MAF see's going on (hovers around 5 + or - .25 - I just don't get how there can be such a difference if the MAF's see the same amount of air flow, why is the car adding so much fuel?
Here is this morning with factory lids, they were at 0.8 and 1.6 driving, went up a little at idle, but never seems to go any higher, in the 5-6% range is the highest I ever see on US lids.
Here is with ROW lids installed, immediately long term fuel trims go into the 20's and stay there
Wow that's a lot.....fingers crossed for the epoxy working out for you.
On a more positive note, your AFR looks so nice and close to 14.7
I just dont understand the deviation between sides.
Originally Posted by roadkillrob
Ok, finally got my ROW airboxes back in after sealing them - mine were very good form the factory, tiny gap I could see light through, sealed them very well and it makes 100% zero difference on my car.
Also notable, MAF's see exactly the same amount of air passing them on both lids, no noticeable difference to what the MAF see's going on (hovers around 5 + or - .25 - I just don't get how there can be such a difference if the MAF's see the same amount of air flow, why is the car adding so much fuel?
Here is this morning with factory lids, they were at 0.8 and 1.6 driving, went up a little at idle, but never seems to go any higher, in the 5-6% range is the highest I ever see on US lids.
Here is with ROW lids installed, immediately long term fuel trims go into the 20's and stay there
Interesting Rob, only question I have is are you sure the seal you made its actually fully sealing the gap? Posible to check with some flowing water to see if it leaks through?
Doesnt make sense why some are seeing drops in the trim values with the seal and your not.
BTW, with the NON row boxes, are you using the factory paper and charcoal filter? If I cant get an improvement with the epoxy then I may just stick with the NON row boxes and afe filters
Look, this does not need to be surprising.
Here is the table for the Subaru:
As you can see, it's called MAF scaling and it's in terms of maf voltage per air flow.
So, when one tunes the car, they start with a log. The log shows the air to fuel ratio and the load.
You also know the ltft.
So the scaling is changed, then the afr goes where it needs to go, but with a very fine scaling change, the ltft is zeroed out.
This is simplistic of course, but for more air going through for the same sensor voltage output, it's normal to see high Ltft with a higher flowing intake.
What is unexpected is that for tuned guys, the tuner did not fine tune the maf scaling for zero or close ltft. Because both tuned and untuned see the same ltft for ROW, seems like the tuner left the scaling untuned and left the ECU to work out what to do.
I deleted my EC V6 tune recently and went back to stock. However when I compare logs of my own tune-in-progress vs the EC tune, the LTFT's are actually quite similar. This may well be down to me having fairly fresh/new o2 sensors though (August), as the car immediately felt a lot nicer to drive once I'd swapped them out.
I still have a very small variance between both sides at times (2-3% on average) but I figure it's somewhat normal, seeing as each cylinder has it's own struggle in terms of equal air distribution and then also we need to consider fuel flow via the injectors.
The bias between sides is something else that bothered me for a long time.
I was hoping it's the injectors, but after new injectors the bias did not equal out and did not change sides.
Then I thought maybe there is a weak point resulting in a hairline crack in the stock exhaust manifold, which all get on the same side.
But then headers guys also have this problem.
I think an important question is :
Do we all have the bias on the same side and is the percentage of the bias comparable ?
If everyone has the same side and by the same amount, maybe it's in the construction ...
The rails are fed in parallel, but the feeding point is not in the middle of the connecting pipe.
My side 1 is his higher between 2-4.5%.
After sealing the ROW, the bias became larger, probably I sealed one side better.
Then after sealing the US boxes dropped close, looking at the graph it's tighter than before, but side 1 is still higher, so it's injecting more fuel there.
the best standalones have per cylinder fueling adjustments. even with things as perfect as you can get there still can be variation between cylinders. you'd need to flow bench each port, flow bench each injector, and test swirl for each cylinder to even tell you how much variation you have mechanically.
i'd say keep digging, but with a 2%-4.5% variation it might easily come down to something you aren't able to fix. good luck!
ok well I feel dumb...my trims are fubar NOT because of air leakage...it's because I actually did the "ROW Mod". the way the air is flowing over the sensor is entirely different now and at idle more air is flowing around the sensor than through it. Same with low speed sudden change of throttle causing dips in engine response.
look at all that lovely unmetered air bypassing the sensor body. stupidest mod ever. now I need to figure out how to remedy this mod by building a wall or something.
the only way around this is to have a completely custom tune built with low/mid throttle sections of the map adjusted for.
Last edited by hachiroku; Dec 22, 2017 at 07:53 PM.
12 C63BS Magno Alanite Grey, 25 X5 Msport, 08 BMW E93, Ducati Hyper 698
They are well sealed, nothing getting passed them I am sure but will test with some water.
With the non ROW boxes, totally factory, charcoal inserts and MB paper filters I may just stick with them also at this point.
Originally Posted by bentz69
I just dont understand the deviation between sides.
Interesting Rob, only question I have is are you sure the seal you made its actually fully sealing the gap? Posible to check with some flowing water to see if it leaks through?
Doesnt make sense why some are seeing drops in the trim values with the seal and your not.
BTW, with the NON row boxes, are you using the factory paper and charcoal filter? If I cant get an improvement with the epoxy then I may just stick with the NON row boxes and afe filters
I can concur with Rob. My ROW is very well sealed at the inlet. US box shows mid one digit vs ROW showing 25 & 23. This does goes against closed loop theory, same MAF sensor (pulled them out and checked part number), same amount of air passing through MAF, no leaking, and US one registeres normal LTFT. I think on this thread, only one success story is from UK where ROW is stock? But even if there is diff in Europe tune vs US tune, same amount of air get registered...very strange. I am going to run US box. Although my car runs smooth with ROW, I do not like 20+ LTFT at idle.
So i got the dash command reading, the LTFT bank 2 was 2.3 at idle, drove a bit and check again was 3.1. Unlike the STFT, is a steading number not hoovering up or down.
By the way, what timing are you guys geeting at idle.
my is hooverin up down 14-20. I thought timing would be fixed at idle?
So i got the dash command reading, the LTFT bank 2 was 2.3 at idle, drove a bit and check again was 3.1. Unlike the STFT, is a steading number not hoovering up or down.
By the way, what timing are you guys geeting at idle.
my is hooverin up down 14-20. I thought timing would be fixed at idle?
Nice ^
14 to 20 at idle is good man. Nothing to worry about.
anytime your long terms are not close to 0% your short term is doing lots of swing adjustments. basically your fueling map is incorrect.
as fast as our ECU's can make adjustments you have milliseconds of throttle and engine response at stake. additionally fuel maps that are VERY off can cause engine failure in boosted engines. again these may not be "fuel" map issues. there could be air leaks, etc etc. all mechanical items should be addressed before pointing to a fuel map as fuel maps are built off perfectly running engines with zero issues.
the reason why tuners can easily build tunes that encompass many hardware items for the M156 is because the engine itself has the same volumetric efficiency. with changes to "external" hardware you will have slight variations to the tune of which the HIGHLY intellegent Bosch Motronic ECU can make adjustments to. our factory computers are "smart" computers and will make fueling and timing adjustments on the fly.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Just for another data reference point, at idle with Carbonio air boxes my LTFT is pegged at 25% for both sides. There are no leaks and nothing to seal as they’re molded carbon throughout.
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